On Wed 24-09-25 14:05:52, Jeff Layton wrote:
> In order to add directory delegation support, we need to break
> delegations on the parent whenever there is going to be a change in the
> directory.
> 
> Add a delegated_inode parameter to lookup_open and have it break the
> delegation. Then, open_last_lookups can wait for the delegation break
> and retry the call to lookup_open once it's done.
> 
> Signed-off-by: Jeff Layton <[email protected]>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <[email protected]>

                                                                Honza

> ---
>  fs/namei.c | 22 ++++++++++++++++++----
>  1 file changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/namei.c b/fs/namei.c
> index 
> 4e058b00208c1663ba828c6f8ed1f82c26a4f136..903b70a82530938a0fdf10508529a1b7cc38136d
>  100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -3609,7 +3609,7 @@ static struct dentry *atomic_open(struct nameidata *nd, 
> struct dentry *dentry,
>   */
>  static struct dentry *lookup_open(struct nameidata *nd, struct file *file,
>                                 const struct open_flags *op,
> -                               bool got_write)
> +                               bool got_write, struct inode 
> **delegated_inode)
>  {
>       struct mnt_idmap *idmap;
>       struct dentry *dir = nd->path.dentry;
> @@ -3698,6 +3698,11 @@ static struct dentry *lookup_open(struct nameidata 
> *nd, struct file *file,
>  
>       /* Negative dentry, just create the file */
>       if (!dentry->d_inode && (open_flag & O_CREAT)) {
> +             /* but break the directory lease first! */
> +             error = try_break_deleg(dir_inode, delegated_inode);
> +             if (error)
> +                     goto out_dput;
> +
>               file->f_mode |= FMODE_CREATED;
>               audit_inode_child(dir_inode, dentry, AUDIT_TYPE_CHILD_CREATE);
>               if (!dir_inode->i_op->create) {
> @@ -3761,6 +3766,7 @@ static const char *open_last_lookups(struct nameidata 
> *nd,
>                  struct file *file, const struct open_flags *op)
>  {
>       struct dentry *dir = nd->path.dentry;
> +     struct inode *delegated_inode = NULL;
>       int open_flag = op->open_flag;
>       bool got_write = false;
>       struct dentry *dentry;
> @@ -3791,7 +3797,7 @@ static const char *open_last_lookups(struct nameidata 
> *nd,
>                               return ERR_PTR(-ECHILD);
>               }
>       }
> -
> +retry:
>       if (open_flag & (O_CREAT | O_TRUNC | O_WRONLY | O_RDWR)) {
>               got_write = !mnt_want_write(nd->path.mnt);
>               /*
> @@ -3804,7 +3810,7 @@ static const char *open_last_lookups(struct nameidata 
> *nd,
>               inode_lock(dir->d_inode);
>       else
>               inode_lock_shared(dir->d_inode);
> -     dentry = lookup_open(nd, file, op, got_write);
> +     dentry = lookup_open(nd, file, op, got_write, &delegated_inode);
>       if (!IS_ERR(dentry)) {
>               if (file->f_mode & FMODE_CREATED)
>                       fsnotify_create(dir->d_inode, dentry);
> @@ -3819,8 +3825,16 @@ static const char *open_last_lookups(struct nameidata 
> *nd,
>       if (got_write)
>               mnt_drop_write(nd->path.mnt);
>  
> -     if (IS_ERR(dentry))
> +     if (IS_ERR(dentry)) {
> +             if (delegated_inode) {
> +                     int error = break_deleg_wait(&delegated_inode);
> +
> +                     if (!error)
> +                             goto retry;
> +                     return ERR_PTR(error);
> +             }
>               return ERR_CAST(dentry);
> +     }
>  
>       if (file->f_mode & (FMODE_OPENED | FMODE_CREATED)) {
>               dput(nd->path.dentry);
> 
> -- 
> 2.51.0
> 
-- 
Jan Kara <[email protected]>
SUSE Labs, CR

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